The present invention relates to a cleaning device for removing a developer remaining on a recording element which is installed in a recording apparatus and, more particularly, to a cleaning device for removing residual toner and like developer particles from a photoconductive element of an electrophotographic copier or the like which may be formed as a sheet or a belt.
In an electrophotographic copier, for example, a latent image electrostatically formed on a photoconductive drum or belt is developed by a developing unit and then transferred to a paper sheet by a transfer unit. Usually, a cleaning device is installed in such a copier in order to remove toner and other developer particles which remain on the surface of the drum or the belt after the transfer of the developed image. The cleaning device comprises, for example, a cleaning sleeve which has a length substantially equal to the width of the photoconductive element and is located to face the photoconductive element. A cleaning brush is formed on the surface of the cleaning sleeve using a suitable material, so that it may contact the surface of the photoconductive element to remove the residual toner. A primary requisite for effective cleaning is, therefore, that the cleaning brush formed on the cleaning sleeve and the surface of the photoconductive element be constantly held in even contact. Some implementations have heretofore been proposed to satisfy the requisite and have proved to be useful individually.
However, a problem has been encountered with such a cleaning device in that after a long time of use of the copier the pressing contact of the cleaning sleeve with the surface of the photoconductive element becomes uneven in the widthwise direction of the photoconductive element, tending to bring about irregularity in the cleaning operation. The even cleaning effect is unattainable especially when the width of a developing sleeve in the developing unit is varied due to aging until the distribution range or the deposition condition of the residual toner on the photoconductive element has changed. Meanwhile, in an intermediate portion of the cleaning sleeve which remains in contact with the residual toner on the photoconductive element while attracting it thereonto, the toner is usually scraped off by a blade or the like and then discharged to the outside. However, the toner progressively accumulates on the cleaning sleeve as the time lapses with the result that the diameter of the cleaning sleeve intermediate portion gradually changes and, eventually, becomes larger than the diameter of opposite end portions of the sleeve which hardly touch the residual toner on the photocondutive element during cleaning. This causes the cleaning sleeve to contact the surface of the photoconductive element with different pressures at the intermediate portion and the opposite end portions, rendering a desirable cleaning effect unachievable.